Salivary immunoglobulin A in healthy adolescent females: effects of maximal exercise, physical activity, body composition and diet.

BACKGROUND

The primary purpose of this study was to examine the effect of acute maximal exercise (VO2max test) on salivary immunoglobulin A (SIgA) responses in adolescent females. A secondary aim was to examine the relationship between resting SIgA levels and VO2max, physical activity, body composition, and diet.

METHODS

Fifty healthy female adolescents completed a laboratory-based VO2max test, assessment of body composition via hydrodensitometry, a validated physical activity questionnaire (PAQ-A), and a three-day food diary. Unstimulated saliva was collected before, and 5 and 120 minutes after VO2max testing. Absolute SIgA (µg/mL) concentration was determined using an enzyme-linked immunosorbent assay. Secretion rate of SIgA (µg/min) was calculated by multiplying absolute SIgA concentration by saliva flow rate (SFR, µL/min).

RESULTS

A significant increase in absolute SIgA concentration (146.8±59.2 µg/mL) was noted immediately after VO2max testing (P<0.05) and returned to pre-exercise levels (120.1±54.1 µg/mL) by 120-min post-exercise (P>0.05). No significant VO2max test effects were observed for SIgA secretion rate and SFR (P>0.05). VO2max values (41.92±6.36 mL/kg/min) were correlated with body fat percentage (r=-0.59; P<0.01), PAQ-A total score (r=0.48; P<0.01), and acute changes in absolute SIgA levels (r=0.28; P<0.05). No significant associations were observed between dietary measures and resting SIgA levels or SFR (P>0.05) except for dietary fiber which correlated with resting absolute SIgA concentration (r=0.29; P<0.05).

CONCLUSIONS

Findings indicate that acute graded maximal exercise results in a transient increase in absolute SIgA concentration and that these changes are associated with individual VO2max values.